Stabilization of oils



and held dispersed in the oil Patented May 12, 1942 SATES 2,282,{ti v TENT FFE

STABILIZATION OF OILS Sidney Musher, New York, N.'

Y., assignor to Musher Foundation Incorporated, New York, N. Y., a corporation of No Drawing. Original I: tion February 25, 1942 Serial No. 348,827.

9 Claims.

The present invention relates to the stabilizacontain a large proporlarly oxidizable and that this deterioration is increased wherever the oils are subjected to high temperature deodorization during the refining process.

It has now been found that when such glyceride oils are heated to relatively high temperatures with combinations of organic, preferably aliphatic, non-aromatic nitrogen compounds such as the proteins including casein and gelatin, zein, the proteoses, albumins, globulins and the amino acids such as glutamic acid, glycine, aspartic acid, alanine or tyrosine on the one hand and a water soluble carbohydrate or sugar such as dextrose or a phosphorus compound such as a phosphatide including lecithin and cephalin or phosphoric acid or its salts on the other hand, instead of losing stability and becoming more subject to deterioration, t e oils will become very stable and highly resistant to oxidative deterioration and rancidity. v

The sugars and the organic nitrogen compounds or the phosphatides and the organic nitrogen compounds are used preferably in equal proportions. They may also be employed in relative proportions varying from about 1 part of the sugar or phosphatide and 10 parts of the organic nitrogen compound. to 10 parts of the sugar or phosphatide and 1 part of the organic nitrogen compound and the combinations are dispersed in the glyceride oil which is then heated or they may be added to the oil during high heat treatment to develop marked antioxygenic effectiveness.

These combinations of the organic nitrogen compounds with either the sugars or phosphorus compounds may be added separately to the oil to be stabilized or may first be mixed in combination and then added to the oil but in either case they are thoroughly dispersed in the oil while the oil is at an elevated temperature in preferably at over 400.

The sugars which are preferably utilized for combination with the proteins or amino acids include particularly the monosaccharides such as dextrose and less preferably'the di, tri or poly saccharides such as sucrose, maltose, lactose and New York ppiication July 31, 194i), ivlded and this applica- Serial No. 432,265

Other sugars that may be utilized for combination with the'organic nitrogen compounds include raw or refined cane or beet sugar, cane or beet sugar molasses, invert sugar or molasses, corn sugar molasses, carbohydrate alcohols, etc.

The preferred combinations for addition to oils followed by heating are mixtures of approximately equal parts of the proteins such as casein or gelatin with the monosaccharides such as dextrose.

The phosphorus compounds employed for combination with the protein or amino acid include phosphoric acid and particularly the phosphatides such as lecithin or cephalin.

The lecithin may be obtained from any source but is preferably obtained from crude soya bean, com or cottonseed oil by precipitation of the lecithin after expulsion or extraction of the oil from the soya beans, corn gems or cottonseed. The lecithin may be in its crudeform or in substantially refined form when utilized for combination with the protein and for dispersal in the oil at the elevated temperature to produce the stabilizing efiect.

Instead of using the phosphorus compound such as the lecithin in substantially purified con-- table excess of 250 F. and

still less preferably dextrin or solubilized and/or gelatinized starch.

dition, it is also possible to use animal or vegematerials which are high in .phosphatide content and which contain 30% to 40% or more total phosphatide content against their solids weight, such as, for example, nerve tissue and brain tissue. i 4

The combination is added in an amount of less than 5% and desirably less than 1%. As little as 0.02% to 0.5% will give highly desirable stabilizing results when the glyceride oils are treated in accordance with this invention.

After dispersing the combination of the organic nitrogen compound with the phosphatide or sugar in the oil, the oil is heated to an elevated temperature, desirably in excess of 250- F. and prefera'bly to between 325 F. and 450 F. for at least 15 to 30 seconds.

It has been found that merely melting a glyceride fat or oil, particularly where the glyceride is solid at room temperature, is not sufficient to give the desired efiect and it is necessary to utilize an elevated temperature substantially above the meltingpoint of the glyceride if it normally be solid at room temperature.

During the heatingperiod, any residue which may become burnt or charred may be removed as by filtration or centrifuging from the body of the oil, asthe stabilization of the oil will already have light color of the oil may teraction the heating 'vated temperature This charring'apparently enhances the action of the combination onthe oil and it has been found particularly desirable for the heating to be sufliciently high so as to produce charring in order to obtain the fully desirable results of the present invention.

The oil which has been heated with the combination will normally be darker as the result of the elevated temperature treatment and the stabilization will have been effected even though the charred residue be removed from the o l as by filtration or centrifuging.

It, however, has been found that the original be restored by a bleaching process as, for example, with fuller's earth or other decolorizing materials and still retainin a substantial enhancement in the stability of the The results 01 the'present invention are par- I ticularly surprising since antioxidants are recognized as losing at least a portion of, and in most cases a major portion of their effectiveness when heated to elevated temperatures such as to 400 F. or more.

Example Bleached refined lard wastreated by adding thereto and mixing therein combinations of organic nitrogen compounds with sugars. The lard containing the combination 400 F. for minutes, allowed to cool, and filtered to remove the charred sugar solids. The

lard was thereupon tested by bubbling air through a cc. sampleof the lard at 125 F. until rancidity as determined organoleptically and hyper-- oxide values was observed. The following results were obtained.

V ing to fal Unhemd F. for 5 minutes Claim; refined bleached lard (no addi- Hours Home!3 ons Lard plus 0.12, dextrose aloud-.. 4 3 ,5 Lard cont 0.1% dextrose plus- 0.1 asparagine 8 19 0.1 o casein 4 13 dispersal of the combination in the oil.

The glyceride may. where-desired, be bleached or otherwise refined after treatment at the elewith the combination and a distinct enhancement of the antioxygenic eflect will be obtained, such enhancement being .iar

in excess of normal expectation.

It is not desirable for the heating to be con ducted in a small body used as a base for addition to. a large body of oil. The most desirable method isfor the combination tobe dispersed in the entire material'to be stabilized, followed by subjecting the oil to a high heat was then heated to a decrease in stability of the the iully enhanced body of 7 Apparently a chemical reaction occurs between the components of the combination and the oil at the elevated temperature whereby the sta bilization is efiected, as this reaction does not appear to be related to ordinary negative oxidation catalysis by means of which antioxidants normally exercise activity.-

The higher the temperature to which the oil containing the combination is subjected, the greater thestabilizing action although the sharpest increase in stabilization is between about 325 F. and 450 F.

The heat treatments need not be prolonged, the enhanced antioxygenic effect being obtained in relatively short periods particularly where the higher temperatures are employed. Normally, the oil containing the combination may merely be heated to the desired temperature ,and allowed to cool, being held at the high temperature for aperiod of 10 minutes or more.

The heat treatment will usually be carried out at atmospheric pressure but the use of super or sub-atmospheric pressures may also be employed with satisfactory results. I

This process may be utilized in the treatment and stabilization of a wide variety of refined or crude glyceride oils such asthe vegetableoils and fats including cottonseed 011, corn oil, pea- I nut oil, linseed oil, soya bean oil, olive oil, etc., the animal oils and fats including lard, tallow. oleo 0il,cod liver oil, halibut liver oil, mackerel oil, menhaden-oil, herring oil, shark liver oil,

butter, etc., the glyceride soap oils and the sulfonated oils.

Not only is the oil stabilized, but components of the oils are also stabilized. For example, the

vitamin A content of .flsh liver and other oils,

the carotene content oibutter fat and similar substances associated with the oils which may be destroyed or reducedby oxidation are highly stabilized by this treatments This invention is, however, particularly bene- I ficial in the treatment of those glycerldes whichcontain large proportions of unsaturated fatty acids, as the combination appears to react more completely with these unsaturated oils at the elevated temperatures.

Although one or more members of the combination may already have some antioxygenic effect when added to the glyceride oils and without the heat treatment, nevertheless. such antioxidant 01 the oil and that oil in order to produce the desired interaction or result. l

persed in such oil.

ried outfor a sufficient length of time to increase the stability by usually not less than 50% power is very greatly increased and enhanced by heating the combination in the oil to over 250 .F. and preferably to 325 F. to 450 F.

The stability of the treated oils will often be enhanced from 50% to 500% or more by the heat treatment in the presence o! these combinations as compared to the stability which would be obtained by the addition of the combinations without the heat treatment described in this invention.

The most important features of the present invention reside in the fact that the added materials are not normally present in the 'oilto be stabilized and upon addition are thoroughly dis- The heat treatment is carover the stability of the unheated oil.

While the combination is dispersed in'the oil at the elevated temperature of, say 400 F., su-

perheated' steam may, where desired, be continuously injected into the oil over a period using as 4 to 6 hours and the objectionable flavors and odors originally present in the oil may be reto high fat containing animal products, heating at atmospheric or elevated pressures to temperatures of about 250 F. so that the glyceride oil or fat contained therein is released from the meat or fish animal product and a highly stabilized animal glyceride is obtained.

Forexample, to a kettle of hog fat containing 70% total glycerides may be added 0.1% of a combination of dextrose and casein against the weight of the hog fat and the combination placed in a steam'kettle with steam being injected into the kettle to produce about 45 pounds pressure. After a 4 to 5 hour treatment, the pressure may be released and the rendered lard removed. The stability of the lard obtained in this manner will be much greater than if the combination had merely been added to the lard after rendering.

For example, when a small amount of a combination of dextrose and casein is added to hog fat and the hog fat containing the combination is then rendered at a temperature of 275 F. for 4 hours, the rendered lard removed from the rendering kettle has a far greater stability than where a proportionate amount of the combination is added to the lard after rendering and the improvement in stability is even greater than where the combination is added to the lard after rendering and the lard containing the combination is then heated to 275 F. for 4 hours. Apparently a further interaction takes place by adding the combination to the rendering kettle where the rendering is conducted at over 250 F. resulting in a most highly stabilized oil.

In a similar manner, a small amount of the combination may be added to the rendering kettle in the rendering of other meat and fish oils and fats including tallow, menhaden oil, herring oil, etc., or to the cooking kettles in the manufacture of fish meals, particularly high glyceride containing fish meals and where the temperature is at least about 250 F., the desired interaction will result producing enhanced stabilization.

Where the glyceride oils are heated over long periods to temperatures over 250 F. and desirably to temperatures over 300 F., small amounts of the combination may be added to the oils at regular intervals of 5 to hours followed by filtration to remove the insoluble portion before adding a fresh amount of the combination. In

this manner, the glycerides will be held in highly stabilized and non-rancid condition over very long periods.

In addition to treating the glyceride oils and fats with these combinations, the essential oils and particularly the oxidizable unsaturated essential and perfume oils such as lemon oil and orange oil may similarly. be treated with the combination followed by an elevated temperature treatment to enhance the antioxygenic effect.

The combinations also exert an enhanced antioxygenic efiect when added in small proportions to the substantially non-volatile, high molecular weight, hydrocarbon oils and particularly the lubricating oils followed-by temperature ordistributed throughout the body of the oil in substantially fine particles and that the heating .be carried out with substantial exclusion of the atmosphere or without contact with air.

It is moreover desirable forthe combination to be maintained in dispersed condition during the heat treatment and so that it will not tend to settle or conglomerate or be present in the form of large lumps or particles since in the latter case the fully desirable-results of the present invention are not obtained.

It is desirable that the oil after treatment in accordance with the present invention will not be materially changed in its odor or fiavor. The oil will, however, have a darker color which may be removed by subjecting it to a bleaching operation;

It has also been found that desirable results are obtained where the combinations are mixed with the oil or fibrous materials containing the glyceride oil and then the oil is'heated to. a temperature of, say from 250 F. to 500 F, under a reduced pressure, such as under a gas pressure less than 1 pound per square inch to cause distillation of part or all of the glyceride oil composition and it has been observed that such distilled fraction is highly stable and is also free of the combination which has served as the stabilizing agent at the elevated'temperature of distillation. a

After treatment of the glyceride oil with the combination at the elevated temperature, the unsaponifiable fraction may be removed as by alcoholic extraction and said unsaponifiable fraction utilized for addition toother oxidizable oils to protect them against oxidative deterioration.

Where caseinogen is utilized, which caseinogen already contains a certain phosphorus content.

the cas'einogen along may be added to oils, particularly glyceride oils followed by heating to in excess of 250 F. and an enhanced antioxygenic effect is obtained.

-matured into Patents 2,198,200,

In the use of the phosphoproteins, lecithoproteins or nucleoproteins in accordance with the present invention, where those materials are added to oils and particularly glyceride oils and the oils then heated to at least 250- F.'., an en hanced antioxygenic effect is also obtained.

The present application is a division of application Serial No. 348,827, filed July 31,1940, and

through said application is a continuation in part of application Serial No. 247,631, filed December 24, 1938.

Through the latter application Serial 'No.

247,631, the present application continues in part the subject matter of the applications which 2,198,210, 2,198,211 and 2,198,215.

Having described'iny invention, what I claim is: '1. A process of stabilizing oils subject to oxidative deterioration, wherebythey become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a material selected from the group consisting of the phosphatides,

phosphoric acid and the salts of phosphoric acid and an organic nitrogen compound selected from the group consisting of the proteins and amino treatments of over 250' F. and preferably beacids, and heating to in excess of 250 2. 'A process of stabilizing oils subjectto oxidative deterioration, whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small solids of the combination be uniformly dispersed 7s amount of a combination of aphosphatide' and a protein, and heating to in excess of 250 F. while the oil is under sub-atmospheric pressure.

3. A process of stabilizing glyceride oils sub-. ject to oxidative deterioration whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a phosphatide and casein, and heating to in excess of 250 F. 4

4. A process of stabilizing oils subject to oxi-. dative deterioration whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a phosphatide and an amino acid, and heating to in excess of 250 F.

5. A process of stabilizing oils subject to oxidative deterioration whereby they become less subjectto such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a phosphatide and tyrosine, and heating to in excess of 250 F.

6. An oil normally subject to oxidative deterioration carrying the reaction product of a combination of a material selected from the group consisting of the phosphatides, phosphoric acid and the salts of phosphoric acid and an organic nitrogen compound selected from the group 'conoil, saidreaction product having been formed by heating" the combination in the oil to in excess sisting of the proteins and aminoacids in the 7. A glyceride oil having a high proportion of unsaturated glycerides, said 011 being normally subject to oxidative deterioration, said oil carrying the reaction product of a combination of a phosphatide and an. organic nitrogen compound selected from the group consisting of the proteins and amino acids, said reaction product having been formed by heating the combination in the oil to in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

8. A glyceride oil normally subject to oxidative deterioration carrying the reaction product of a combination of a phosphatide and a protein, said reaction product having been formed by heating the combination in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

9. A process of stabilizing glyceride oils subject to oxidative deterioration, whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a material selected from the group consisting of the phosphatides, phosphoric acid and the salts of phosphoric acid and an organic nitrogen compound selected from the group consisting of the proteins and amino acids, heating to in excess of, 250 1".

and removing the unsaponifiable fraction therefrom.

- SIDNEY MUSHER. 

